1. Field of Invention
The invention relates to communication systems, and in particular, to two-way communication systems utilizing multiple transceivers.
2. Related Art
Simple two-way communication systems such as internal communication systems (i.e., “intercom systems”) are well known in the art for allowing multiple users to communicate with each other via a simple communication network. Intercom systems are usually designed for station to station dialing within a specific location such as a building. Generally, the intercom system includes a plurality of communication devices (also known as “stations”) where each communication device is assigned an identification key that allows each communication device in the intercom system to communicate with the other individual communication devices by utilizing the identification key (also known as station-to-station dialing). Unlike most telecommunication systems, such as telephone networks or wireless communication networks, typical intercom systems allow users located within a location (such as a building) to call other users located within the same location without using an outside communication network such as a telephone (i.e., an outside line).
FIG. 1 shows a typical known intercom system 100. The intercom system 100 may include multiple communication devices that are in signal communication with each other and are capable of communicating individually between communication devices or communicating in a broadcast mode from an individual communication device to all other devices in the intercom system 100. As an example, the intercom system 100 may include three communication devices, such as first communication device 102, second communication device 104, and third communication device 106. While three communication devices are shown in FIG. 1, it is appreciated by those skilled in the art that the intercom system 100 may include optionally any number of communication devices, from two communication devices to as many as desired. An as an example, the first communication device 102, second communication device 104, and third communication device 106 may be implemented with wired or wireless intercom modules that are in signal communication with each other.
The communication devices may operate in either specific device-to-device communications mode (i.e., station-to-station dialing) or in a broadcast mode. As an example of a specific device-to-device communications mode, the first communication device 102 and second communication device 104 may communicate to each other via signal path 108. Similarly, the first communication device 102 and third communication device 106 may communicate to each other via signal path 110. Moreover, the second communication device 104 and third communication device 106 may communicate to each other via signal path 112.
As an example of a broadcast mode, the first communication device 102 may communicate to both the second communication device 104 and the third communication device 106 simultaneously via signal path 114. Similarly, the second communication device 104 may communicate to both the first communication device 102 and the third communication device 106 simultaneously via signal path 116. Additionally, the third communication device 106 may communicate to both the first communication device 102 and the second communication device 104 simultaneously via signal path 118. The signal paths 108, 110, 112, 114, 116, and 118 may be either wired and/or wireless communication paths.
In an example of operation, the communication devices in the intercom system 100 may include selection switches (not shown) that allow individual communication devices to either communicate in a broadcast mode to all the other communication devices simultaneously or to specific other communication devices in the specific device-to-device mode. Unfortunately, the intercom system 100 does not allow two or more users, located at two or more communication devices, to communicate back and forth simultaneously because typically the intercom system 100 is only a half-duplex type of communication system that allows transmitting in both directions only one direction at a time. Therefore, a user located at the second communication device 104 is not able to simultaneous communicate with the first communication device 102 when the first communication device 102 or the third communication device 106 is transmitting because the second communication device 104 is receiving the transmissions from either first communication device 102 or the third communication device 106.
Attempts to correct this problem may include adding additional electronic circuitry to the communication devices in the intercom system to allow the communication devices to operate in a full duplex mode of operation that would allow simultaneous transmissions in both directions. For example, frequency division multiple access (“FDMA”), time division multiple access (“TDMA”), and code division multiple access (“CDMA”) transceivers may be utilized.
However, these approaches are technically complex, expensive, and typically require a high level of technical expertise to implement and maintain. As a result, these types of solutions do not lend themselves to intercom systems that may be easily acquired and installed (i.e., “do-it-yourself systems”) by typical consumers. Therefore, there is a need for a simple communication system of low complexity that is inexpensive, easy to maintain, and may be utilized as an intercom system.